Castin'Craft and pinholes

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spitfire

spitfire

Member
Joined
Dec 22, 2007
Messages
417
Location
bloomsburg,pa.
I ran out of "good" resin and had to use Castn'craft to make a few things. When I turn the blank and final sand I get a bunch of small pin holes that once I sand will in with sanding dust. I clean the blank good and then when I try to use Plastic Polish it stays white inside the little pores. Any ways to get rid of that besides waiting for my new order to come in if Silmar? Hate to waste all this resin.
 
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The pinholes are air bubbles . It's not the fault of the resin but a problem you created by mixing in air as you mixed the catalyst in . Try warming the resin to thin it , use less catalyst (3 drops per ounce) and mix it slowly while keeping your mixing stick on the bottom of your mixing cup .
If you beat the resin to a froth while mixing there will be allot of micro bubbles in the resin that won't have enough time to float to the top before the resin gels . Pressure won't help fix this either , the bubbles are too big to be reabsorbed into the resin but too small to float to the surface quickly .
 
I mix and pour the same as I do with Silmar and never have the problem with Silmar. Is there anyway to salvage what I poured or am I pretty much gonna have to start over with the new resin once it comes?
 
When I've had stubborn pin holes I couldn't get clean I dropped the blank in my ultra sonic cleaner for a minute or so then let dry completely and fill in with thin or med. CA.
 
I don't have an ultra sonic cleaner but I could see how that could work. Hmm CA finish over resin, never did that but have on wood. Worth a shot if I can get the tiny holes clean.
thanks for the input.
 
Are you sure the pinholes are from air during the pour and not from chipouts? I use castin' craft all the time and I never have bubbles in the cast, but I found it will chip horribly sometimes just by looking at it. I found to use a super sharp skew once the square blank is round. Never had a problem.

However to your current situation, like Butch suggested wipe it clean with acetone and use CA to fill.
 
Yeah I'm sure it's not chipout.It's tiny air pockets.

witz1976 said:
Are you sure the pinholes are from air during the pour and not from chipouts? I use castin' craft all the time and I never have bubbles in the cast, but I found it will chip horribly sometimes just by looking at it. I found to use a super sharp skew once the square blank is round. Never had a problem.

However to your current situation, like Butch suggested wipe it clean with acetone and use CA to fill.
Click to expand...
 
Jason talk about a stone throw, I am just over here in Benton, might have to say hay some time..

Jay..
 
Jason , if you bought the resin from Michaels it could have been sitting on their shelves and in the warehouse for quite a while and may have started to go bad . Did it seem to be thicker then you thought it should have been compaired to the Silmar you normaly use ? If it did that could be part of the problem .
 
Might have to take ya up on that some time expecially if your casting, I have always wanted to learn how to cast my own blanks, maybe you could teach an Old Dog some new tricks,..

Jay...
 
With Castin Craft especially, and generically for all resins, I've been happiest when I pour the resin into the mixing cups, and let it air out for a few minutes. Give it a gentle stir every so often to encourage the gas to leave.

Sometimes you'll get a pinhole anyway. Such is life. Gas that coalesced during the curing process, a blob of unmixed pigment or powder, etc.
 
Is Casting Craft the same as Easy Cast from Michaels? If so you mix the two parts in equal amounts. Heat would change the texture wouldn't it?

Also if I understand, by cleaning the blank in the cleaner you're removing all the sanding dust from the holes, then putting CA on to fill in the holes, let it dry, then sand? I am thinking the white in the holes is sanding dust from the blank that's sealed inside the finish? Not sure, just asking.

Montmill
 
For future reference: If you don't have an ultrasonic cleaner, you can put the container of uncatalyzed resin in a frying pan partially filled with very hot tap water. Then, hold the pan over a vibrating sander (with no sandpaper) for 3-4 minutes.

This doesn't work as well as an ultrasonic cleaner, but it will thin the resin and dislodge may of the offending air bubbles.

You can also use this method to try and clean the "goo" out of the air pockets, and then put the blank back on the lathe and fill the clean voids with CA (I perfer medium CA for this task, but any CA will work).
 
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